What about this (Welsh Museum Web site)

I came across this on museum.wales hunting for material on Barry Railway Locomotives. They don't seem to know much about it.
https://museum.wales/collections/on...4-8a77-c7720ab2e9e4/Steam-locomotive-drawing/
I suppose it must be narrow gauge judging by the coupling, but it seems to be a somewhat unusual wheel arrangement. The page says it was donated to them in 1959 and not much else...Anyone know anything?

 

Intriguing. Not quite Nasmyth Wilson (glaringly obvious asymmetric wheelbase). Is that some variant on the Luttermöller theme, ahead of the conventionally coupled drivers? The considerable sideplay implied for the leading bogie scarcely bears thinking about, hence I'm unconvinced as to the practicality of that layout.

 

The odd wheel looks extremely close to the next one, and possible slightly larger diameter as well. Might it be the cog wheel for a rack line?

 

I've seen some weird and wonderful rack locos, but those cylinders look to drive conventionally. Still not convinced this one's a genuine proposal.

 

I'm pretty sure this is one of the Webb compound 4-2-4-2T locos for the 2'6'' Antofagasta (Chili) and Bolivia Railway (FCAB) built by Robert Stephenson & Co in the mid 1880s.

 

Ye Gods! Are we looking at an HP or LP cylinder? There doesn't look to be too much space for an inside LP cylinder, at least not one with a decent con rod length. Please tell me they at least weren't VonBorries system 2 cyl compounds.

 

Some people think the FCAB Webb compound loco survives to this day, in heavily rebuilt form, although it's debatable.
More info and a photo on this page (search for "Webb"): https://www.internationalsteam.co.uk/trains/bolivia01.htm

 

Naturally not, they were Webb 3 cylinder compounds, with the HP cylinders outside driving the rear coupled drivers and an inside LP cylinder driving the front uncoupled drivers...
Just your ordinary run of the mill locos.

 

A typical Webb machine.

See http://www.ferrocarrilesenelconosur.co.uk/Resources/Chilean steam locos 4 sub-metric gauges.pdf for this and a whole host of other magical creations!

Andy.

 

Bit more info here: https://www.steamlocomotive.com/locobase.php?country=Chile&wheel=4-2-4-2&railroad=chile

 

Intriguing. What very peculiar machines. I confess, the only locos on that line I knew much about - and that's not a lot(!) - were the Garratts (what a depressing photo, in your earlier link, of the sad remains one of those formerly impressive locos).

 

I was wondering about a divided drive compound, an inside cylinder was the only thing I could see feeding that first driving wheel. Very odd valve gear too, it seems to be a bit like Joys, but not that much...

 

It is indeed a bit like Joy's...

 

The had many interesting machines. This one was from the 2'6'' era, the line was later regagued to metre gauge. There were Garratts later on, and earlier there were mainline Kitson Meyer tender locos, a few 4-8-2Ts and many large 2-8-4Ts, and post war some handsome and powerful 4-8-2s from North British. Plus many 2-8-0s, some Henschel pacifics, and various locos regagued from 2'6''.

 

Some photos here: https://www.gwrarchive.org/site/sitel2pg/Chile/fcab/fcab.php and here:. https://www.gwrarchive.org/site/sitel2pg/Bolivia/fcab_b/fcab_b.php

 

Great site. Thanks for posting. Just been looking at the Bolivian lines and they've some ambitious plans. Bolivia has significant lithium deposits, which assuming the depressingly familiar habit of Latin American bigwigs to trouser any inflowing largesse, or US corporates financing fascistic coups doesn't get followed yet again, the mineral rights might even allow to be realised. Bob only knows, the population is long overdue for a break.

 

Further to that: it looks to me as if there would be no space at all between the odd wheel and the next one, and they would overlap. If so, the odd one must be in a different place, which strengthens the argument for a rack line.

 

I'm now sure this is the FCAB Webb loco. See the link in post #9.

 

Wow! Only 1/3 or the way through that lot, but what a great resource .... complete with some Double Fairlies whose existence was hitherto unknown. Cheers for posting that one.

I love the phrase 'approximately 3ft gauge', though the only example of a line using an 'approximate gauge' which comes to mind was the Talyllyn, pre-1953!

How I wish a trip to catalogue any (probably very few) survivors were possible. There's a MW 0-6-0T in that lot which would've looked great in a couple of locations I could think of.

 

I wondered about that, and drew it up. They don't overlap, but I have grave doubts about the brakes as drawn.